Cushioned valve tappet



March 25, 1930. W F, FORTH l 1,151,716

CUSHINED VALVE TAPPET Fild April 26', 192e y IHIIII II lll' 31am/nto@@Miou/WMO I liatelnt-ed Mar. 25, A19230 d PATENT OFFICE WILLIAM F.PORTE, OF DETROIT, MICHIGAN CUSHIONED VALVE TAPPET Application led April26,

The invention relates to cushioned valve tappets and more especially totappets provided with fluid pressure cushioning means.

The invention contemplates, in valve op- 6 erating mechanism employinglubricated tappets, the utilization of this source of fluid forproviding cushioning means for plunger elements forming a part of eachtappet and which constitute the direct bearing conne:- 1o tion betweenthe tappet and the valve stem.

By such a construction several noteworthy advantages are obtained, theprincipal of which, however, is that of eliminating the noise incidenttothe engagement of the tap pet with the valve stem. This particularadvantage is obtained because I`the cushioning means maintains theplunger element of the tappet normally projected or extended a distance'substantially equal to the usual clearance provided between the tappetand the cam shaft so that in eiect a longitudinally resilient column iseiected between the cam shaft and the valve stem whereupon the noiseincidentto the slapping engagement between the cams and the tappets iseliminated; The

amount of pressure maintained and the extent of leakage between thetappet and plunger is such that the plunger reciprocates or telescopeswith the tappet V'upon each. reciprocation of the tappet so that theplunger is maintained in Contact with thevalve stem substantiallycontinually and the objectionable noise incident to the operation oftappet valves eliminated.

The invention contemplates various other objects, advantages and noveldetails of construction, all o which will be made more apparent as thisdescription proceeds, especially when considered in connection with theaccompanying drawings, wherein- Figure 1 is a fragmentary side elevationpartly in section, of a valve operating mechanism embodying myinvention, and

Figure 2 is an end elevation thereof.

Referring now particularly to the drawings wherein like referencecharacters indicate like parts, 1it will be noted that there isillustrated fragmentarily a valve cam shaft 10 provided with a-pluralityof cams 11 equal in number to the valves to be operated, the

1926. Serial No. 104,863.

stems 12 of which are fragmentarily illustrated.

The reference character 13 indicates the tappet bearing frame in whichthe tappets 14 are mounted for reciprocation in the cus- 55 tomarymanner by the cams 11. Each tappet 14 is provided with a longitudinalbore 15 the upper end of which is interiorly threaded for the receptionof a tappet adjusting screw 16. The upper end of the tappet adjustingscrew is provided with a bore 17 of reduced diameter and with a circularrecess 18. Associated with the outer or upper end of each adjustingscrew 16 is a plunger element 19 having a shank portion 30 which titsinto the G5 bore 17 and a head portion 21 of a diameter to snugly fitthe circular recess 18. The plunger element 19 is consequently sldablyor reciprocally mounted in the upper end of the tappet 14 and tends toseat itself by grav- 70 ityl with the head -21 thereof resting in thebottom of the recess 18.

. The bearing frame 18 is provided with a longitudinally extending boreor passageway 22 extending past the several tappets 14 75 through whichlubricating oil is supplied to the tappets, this passage-waycommunicating approximately at the center thereof, with a supply conduit23 connected to a suitable fsource of lubricant supplied under pressure.S0

Thus lubricant is fed into the passage way 23 and thence laterallythrough the longitudinal passage-way 22 in both directions as indicatedby the arrows and past the several tappets 14, Each tappet is formedwith a circumferentialv recess or groove 24 communicating by one or moreapertures 25, withthe interior or bore l5 of the tappet. Thecircumferential slot 24 is of suiicient width as to always connect withor remain in communication with the bore 22 during the reciprocation ofthe tappet 14. Thus, fluid under pressure, inthe present linstancelubricating oil, will be constantly supplied to the interior of eachtappet. t. .95 The pressure of the lubricant within the bore of thetappet is suicient inthe idle position of the cam 11, to force plungerelement 19 upwardly to the position illustrated in the drawing, in whichposition it bears against the lower end of valve stem 12. Lubricantwithin the bore 15 also escapes upwardly around the shank portion 20 ofthe plunger to fill the space between the head 21 and the bottom ofrecess 18. When subsequently the cam 11 is rotated to the other positionillustrated in Figure 1 and the tappet 14 has consequently been moved inan upward direction to open the valve, the plunger element 19 will havebeen forced downwardlyto a position where the head 21 is seated in4 therecess 18. During this movement the fluid in the bottom of the recess 18has been displaced by the head 21 and it has also been necessary for thelower end of the plunger 19 to displace the fluid in the bore 15sufficiently to permit this plunger to telescope within the tappet 14.During continued rotation of the cam and its return tothe firstdescribed position, the pressure within the bore 15 of the tappet againurges the plunger upwardly. Consequently the plunger is maintained inengagement with the end of the valve stem and its. telescopic movementwith reference to the tappet cushioned or checked.

Obviously the device is distinguishedb its simplicity which, however, inno wise a fects its eiciency of operation. In the type of installationwith which the invention is herein shown as associated, the lubricatingsystem already forming a part thereof, may be conveniently employed asthe source of fluid pressure for cushioning the plunger of the tappet sothat the device is commercially satisfactory and acceptable because itdoes not involve any radical rearrangement or redesigning of what nowconstitutes standard equipment. Obviously in other forms of valveoperating mechanism the invention may however, be introduced without anyserious rearrangement of the parts.

Reservation is made to make such changes in the details of constructionherein illustrated as may come within the purview of the accompanyingclaims.

lVhat I claim as my invention is:

1. In a valve operating mechanism, a valve tappet formed with a centralbore, means for constantly supplying fluid under pressure to said boreand a valve stem engaging element slidable in said bore adapted forabutting engagement with said valve tappet and cushioned by said fluid.

2. In a valve operating mechanism, a valve tappet formed with a centralbore, means for constantly supplying fluid under pressure to said boreand a valve stem engaging element constituting the bearing connectionbetween said tappet and the valve stem slidable in said bore forabutting engagement with said valve tappet and cushioned by said fluidunder pressure.

3. In a valve operating mechanism, a tappet including a tubular bodymember, a tubular adjusting member wit-hin sa1d body member,

a plunger slidably mounted in the said tubular adjusting member andabuttingly engageable therewith, and fluid pressure means yieldablyresisting abutting engagement of the said plunger with the saidadjusting member.

4. In a valve operating mechanism, a tappet including a tubular bodymember, a tubular adjusting member threadedly mounted in one end of thesaid body member, a plunger slidably mounted in the end of the tubularadjusting member and abuttingly enggeable therewith, and fluid pressuremeans for yieldably resisting abutting engagement of the said plungerwith the said tubular adjusting member.

5. In a valve operating mechanism, a cylindrical valve tappet formedwith a longitudinal bore, a valve stem engaging member having a shankportion slidably received in said bore and an enlarged headed portionabuttingly engaged with the end of said tappet, and means supplyingfluidpressure to said bore for cushioning said member.

6. In a valve operating mechanism, the

ycombination with a reciprocating valve stem,

of a tappet having a tubular portion supplied constantly with a lujdunder pressure, and an element telescopically engaging and movf able bysaid fluid under pressure rela-tive to the tubular portion of saidtappet, the said element being maintained in engagement with the valvestem during movement thereof and its telescopic movement with referenceto the tappet being cushioned or checked by the fluid under pressure.

7. In a valve operating mechanism, the combination with a reciprocatingvalve stem, of a tappet havin a tubular portion, an elementtelescopicaly engaging and movable relative to saidtubular portion, andmeans for supplying constantly a fluid under pressure to the tubularportion of said tappet so that the said element will be maintained inengagement with the valve stem and the telescopic movement thereof withreference to the tappet will be cushioned or checked.

8. In a valve operating mechanism, the combination with a reciprocatingvalve stem, of a tappet'having a tubular portion supplied with fluidunder pressure, a. valve stem engaging element telescopically arrangedwith respect to said tappet, a seat for said element adjustablyconnected to said tappet, and means for supplying fluid under pressureto the tubular portion of said tappet to maintain the element inengagement with said valve stem and to oppose and resist movement ofsaid element upon the adjustable seat.

In testimony whereof I allix my signature. v WILLIAM F. PORTH.

